October 27, 2011

How to Paint a Concrete Floor

After I’ve posted about having painted floors in the basement I’ve had quite a few questions on the process and requests for a how-to. So while I painted the floor in the main room downstairs a couple of weeks ago I took step by step photos to try and explain how I’ve done it. Please don’t just take my word for how it’s done though, check with your local paint store to make sure you get the proper paint for your floor. Anyway here’s how I do it (and it’s according to the instructions on the can of the paint I use which is Alcro Entré).

When we moved in I wanted to get my storage shelves up asap so I painted the space where they were going and left the rest untouched until now. As you can see the floor wasn’t looing too great. Quite a lot of wear and tear and lots of flaking areas. There was probably a rug there at the far end since that area is much less used.

I started out by cleaning the floor with a cleaner that degreases it and leaves it with a matte finish. You mix it with water, wipe the floor with it and then rinse. “Rinsing” basically means you need to get every bit of the cleaner and dirt off before you can paint. Since I couldn’t hose the floor off I got a clean mop head out and changed the water in my bucket a zillion times until the water was no longer cloudy.

That left me with a clean matte surface but also with areas of more peeling and flaking paint which is why it’s important to do this before scraping and sanding because otherwise you’ll end up doing it twice…

After the floor had dried I used a wire brush and sandpaper to smooth out those rough patches. If It didn’t have my shelves full of stuff in that same room I’d have used my mouse sander for this but I didn’t want it all to be covered with dust so I did it by hand. Not the most fun of jobs.

So now the floor was clean and smooth and I’d vacuumed it to remove all the dust so I could actually start painting. As with most paint jobs the prepping time is much longer than the actual painting time so by the time I was this far ahead I knew t was the home stretch.

When painting a concrete floor, if there are bare concrete patches you paint those first with a 90% paint + 10% water ratio. I guess the diluted paint adheres better to the concrete that way.

That left my floor looking like it had typhoid fever or some similar illness. As you can see there were a lot of bare patches at the bottom of the photo and this is the highest traffic area, from the doorway and through to the hobby room door which is where I was standing taking this photo.

After that was done I left the floor to dry. It says 3 hour between coats but the advice I got from my paint store was to leave more time in between the first and second coats for a stronger floor so I left about 12 hours or so between coats and painted three coats altogether including this first spotty one.

And here’s the final result again. If you look closely (on the actual floor) you can still see a world map of where the bare concrete patches once were. I guess if you want a perfectly smooth floor you need to fill those patches first before painting. Since this is the basement I wasn’t willing to take those extra measures and this looks good enough for me. In case you’re wondering about the name of the color I chose, it’s a grey straight off the neutral gray scale; NCS N-2000.

Så snyggt! Will you add any window curtains or other possible places for color? Seems like a cold place to sleep in winter, are there any radiators down there? Really inspiring! We have a similar space full of skräp and need an extra bedroom for guests, but unfortunately there is an ugly plastic floor on top of the concrete. Do you think we should remove the plastic floor (looks like your lino in the hall but is from the 1980 s and is in very good condition)?

The prep work, yes. It's kind of like with the cutting - measure twice, cut once. I am painting my daughter's room this week and there was less prep there than in your basement, but the prep takes longer than the actual painting, as you said. In case you want to have a look http://polonicahomeagain.blogspot.com/ .

Surprisingly the basement is really dry and warm and there's a large radiator in there and when the dryer is on in the laundry room it's almost too warm :). I've never had a basement where I can go in T-shirt only!

Plastic on concret is not great because it traps dampness so if you can, I suggest rip it out. Wood is also not great in a basement unless you add some ventilation under the floor which is usually tricky because you get even lower ceilings that way. Tile is good though, it allows the concrete slab to breathe from what I understand.

Oops, missed your curtain question. Yes, I will add something in front of the windows because I intend to use this space to Zumba and I so don't want a neighbor audience from the street when jumping around uncoordinatedly down there :): There's an old curtain track already up so I may use that.

What a beautiful clean, bright and airy guest room. I'd stay there :) Our lower level (walkout, not basement) is all ceramic tile above concrete floor. It is very dry, but cold. My husband now wishes he had installed radiant heat under the tile. Oh well, good excuse to buy rugs!

beautiful ! it looks so air & clean !
i was wondering if one needs to seal it or if it the paint keeps well in time by itself ?
(i painted a tiled floor with the appropriate paint and from the DIY store + instructions it didn't require any sealer, but after one year we still had a few flakes...)
anyway, a coat of white makes so much difference ! you're going to enjoy your basement life now :)

No sealant is necessary but you do need to be really careful with the prep work and also to let the floor cure properly. The paint store recommended three weeks so I have another week to go until I can start dragging stuff, walking with sandy shoes on the floor etc. I know I assembled the shelves too quickly and where the uprights are there were scratches (which I've now painted over). After three weeks it gets really hard and heavy duty though.

I have a tip for you if you ever have to do this again. Don't change the mop water a zillion times-- get two buckets. One of them you will never put your mop water in-- just pour water out of it straight onto the floor, mop it up, then wring your mop out in the other bucket. After going over everything once, clean your mop head well and do it again. I invented this method when acid-staining a large concrete floor in my brother's church-- you have to get up all the etching acid before you can put the finisher on. Everyone else was changing their mop buckets a million times, and I was working twice as fast!

The result is beautiful! With so many spots that needed to be prepped with the 90/10 paint/water mixture, would it have been ok to do a complete first coat with that, then follow with a few coats of full strength paint?

I love it! In New England, especially at summer houses on the shore and islands, people paint wood floors and concrete floors and then splatter them. I know it sounds tacky/ messy, but it is actually the neatest and sweetest treatment!

is this the same area that you installed the curtains? I believe there were three panels & you hung the curtains from the ceiling & used pinch pleat tape. If so, this looks sooo very cozy... of course, your homes seem to ooze coziness! nice set of instructions.
thanks & have a nice weekend. looking forward to the next project report. ummm, have to ask??? do you ever get tired of sharing so many of your decorating tips with your bloggers? do you enjoy it? or has it become a chore?
Also, could you remind us when you actually moved into Chez Larrson 2?

actually yes maybe we walked on it too soon... but my feeling was the paint was sensitive to the floor detergent, as the flakes occured many months later ... not sure though. might try another brand. anyway thank you for your reply and again, your basement looks GREAT !

Hi Benita, love the floor! I'm getting ready to paint our concrete porch, but had read that I need to strip the old paint off first. Is that true? The porch was painted a few months ago, but the wrong colour. I really want to paint over it but the thought of using paint stripper is really putting me off :( Any tips would be much appreciated!

I can't really see why you'd need to strip the paint off if you just want to change the color. That to me would just be another coat if you use the same brand paint. I would ask again at the paint store. You may need to degrease the surface first before adding another coat if it's been out in the open for some months though.